Honing tool arrangements

ABSTRACT

A honing tool arrangement which includes a tubular shaft to one end of which can be attached a honing tool and the tubular shaft and the honing tool are capable of being reciprocated and rotated, a control rod in the tubular shaft and associated with a piston and cylinder device to cause fast feed longitudinal movement of the control rod relatively to the tubular shaft to cause fast increase and decrease of the effective cutting diameter of the honing tool and disengageable screw means between the tubular shaft and the control rod and rotational brake means associated with the control rod and capable of &#39;&#39;&#39;&#39;braking&#39;&#39;&#39;&#39; the rotation of the control rod relative to the tubular shaft when the screw means is engaged to cause slow feed longitudinal movement of the control rod relative to the tubular shaft and thus to cause a slow increase and decrease of the effective cutting diameter of the honing tool.

[451 June 20, 1972 HONING TOOL ARRANGEMENTS [72] Inventor: Anthony James Harratt, Werrington, En-

gland [73] Assignee: Hi-Ton Machine Tools Limited, Selly Oak,

Birmingham, England [22] Filed: Jan. 18, 1971 [21] Appl.No.: 107,034

will? -milllii 3,496,678 2/1970 Engle ..51/34 R Primary Examiner-William R. Armstrong AttorneyFriedmann & Goodman [57] ABSTRACT A honing tool arrangement which includes a tubular shaft to one end of which can be attached a honing tool and the tubular shaft and the honing tool are capable of being reciprocated and rotated, a control rod in the tubular shaft and associated with a piston and cylinder device to cause fast feed longitudinal movement of the control rod relatively to the tubular shaft to cause fast increase and decrease of the effective cutting diameter of the honing tool and disengageable screw means between the tubular shaft and the control rod and rotational brake means associated with the control rod and capable of braking the rotation of the control rod relative to the tubular shaft when the screw means is engaged to cause slow feed longitudinal movement of the control rod relative to the tubular shaft and thus to cause a slow increase and decrease of the effective cutting diameter of the honing tool.

14 Claims, 6 Drawing Figures PMENTEDJUN 2 0 m2 SHEET 20F 4 PATENTED JUN 2 0 I972 SHEET 30F 4 HONING TOOL ARRANGEMENTS SUMMARY OF THE INVENTION According to the present invention there is provided a honing tool arrangement of the kind comprising a tubular shaft means capable of being rotated about its longitudinal axis and reciprocated axially and of having attached thereto the honing tool to be rotated and reciprocated therewith and also including a honing tool diameter control means including a control rod in the tubular shaft means and capable of being moved longitudinally relatively to the tubular shaft means to increase and decrease the effective cutting diameter of the honing tool said control means also including fast and slow feed means to cause fast and slow changes respectively in the effective cutting diameter of the honing tool and said slow feed means including screw means wherein the improvements provided are a screw member on the control rod and a complementary nut member carried by the tubular shaft means so as to be movable rotationally and longitudinally therewith, said nut member being movable into a disengaged position with the screw means to permit fast feed longitudinal movement of the control rod and being movable into an engaged position with the screw member, and rotational brake means associated with the screw means and operative to cause relative rotation of the engaged screw member and nut member whilst the tubular shaft means is rotating to cause slow feed longitudinal movement of the control rod.

BRIEF DESCRIPTION OF THE DRAWINGS.

The invention will now be more particularly described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic perspective view, with a part cut away for clarity, of a honing machine constructed in accordance with the present invention,

FIGS. 2, 3 and 4 are vertical sectional views of a honing tool arrangement and the views are continuations of the lower part of the preceding view,

FIG. 5 is a cross-sectional view of FIG. 4 on the lines 5-5 thereof and on an enlarged scale, and,

FIG. 6 is a view corresponding to a part of FIG. 4 but showing a modification.

For convenience similar reference numerals will be used to denote corresponding parts with regard to FIGS. 1 to 5 and FIG. 6.

Referring to FIG. 1, this illustrates a vertical honing machine having two identical honing tool arrangements 10 and 12 mounted in a horizontal overarm 14 disposed at the top of a pillar 16 extending upwardly from a bed 18 upon which two workpiece tubes (not shown) to be honed can be supported in jigs or fixtures so that the two workpiece tubes can be honed simultaneously. It should be appreciated that whilst the honing tool arrangement will be described as applied to the vertical honing machine, the invention is equally applicable to a horizontal honing machine.

As the two honing tool arrangements 10 and 12 are identical one only will be described as representative of both.

The honing tool arrangement comprises an upper or head assembly 20 which extends from the upper end of the view shown in FIG. 2 to a disconnectable bayonet joint 22 indicated in FIG. 3 at which can be disconnectably connected a lower or connecting assembly 24 also shown in FIG. 4 and to the lower end of which can be disconnectably connected, by a bayonet joint 26, a honing tool 28. The honing tool 28 is of generally conventional construction comprising a tubular body 30 formed at its upper end with a spigot 32 carrying the radial bayonet joint pegs 34 adapted to engage bayonet-type slots in the lower end of the connecting assembly24 to enable the honing tool 28 to be detachably connected to said assembly 24. Mounted within the body 30 is a push-rod 36 which is spring-urged upwardly by a helical compression spring 38 and is formed with two downwardly convergent frusto-conical cams 40 which bear on complementary shaped carriers 42 for The head assembly 20 includes a tubular shaft portion 46 I and the connecting assembly 24 comprises a tubular shaft portion 48 connected by a universal joint 50 to a tubular shaft portion 52 which is provided at its lower end with the bayonet joint slots for the bayonet joint pins 34.

The tubular shafts 46, 48 and 52 form a tubular shaft means which is rotatable about the vertical longitudinal axis XX and for which purpose the tubular shaft portion 46 is externally splined to receive a splined toothed bevel wheel 54 which meshes with a driving toothed bevel wheel 56 secured to a shaft 58, see FIG. 1, of an electric motor 60 and the two bevel wheels are housed in a box 62 whereby a fixed ratio gearbox is provided and this gearbox is secured to the stationary overarm 14. In this way when the motor 60 is operated the honing tool 28 is rotated about the axis XX.

In order to reciprocate the honing tool 28 longitudinally of the axis XX and thus vertically the tubular shaft portion 46 is anti-fricationally mounted by both radial and thrust bearings indicated generally at 64 in a cross-head 66 provided with bushes 68 which can slide vertically along vertical guide rods 70 secured to and extending downwardly from the overarm l4 and supported at their lower ends in brackets 71 of the pillar 16 and secured to the cross-head 66 are piston rods 72 of fluid-pressure operated piston and cylinder devices 74 of which the cylinders are secured to the overarm 14. Thus, when the devices are extended and contracted the cross-head 66 and thus the honing tool 28 are moved downwardly and upwardly respectively relative to the stationary workpiece tube being honed.

Secured to the stationary gearbox 62 are two vertical guide posts 75 connected at their upper ends by a cross-bar 76 and the upper end of the tubular shaft portion 46 is mounted in anti-friction bearings 78 in a slide 80 mounted on the guide posts 75.

Rigidly supported by the slide 80 is a body 82 composed of a plurality of parts rigidly secured together so as to be reciprocable with the slide 80 and mounted at the upper end of the body is a rotational brake means 84. The brake means 84 is a rotational liquid brake means of a kind sold under the trade mark Kinetrol as a rotary dash-pot and comprises a non-rotatable brake element 86 and a rotatable brake element 88 and between the elements and in contact therewith is a viscous liquid which is capable of exerting a braking or drag effect on the rotatable element and this braking or drag effect is adjustable by adjustment means comprising a manually rotatable adjustable nut 90 which has screw-threaded engagement with a plunger 92 to which the non-rotatable brake element 86 is secured so that manual rotation of the nut 90 results in moving the non-rotatable brake element 86 nearer to or farther away from the rotatable brake element 88 whereby the drag effect can be increased and decreased respectively.

The rotatable brake element 88 is secured to a spindle 91 mounted in anti-friction bearings and is connected to a friction plate 93 of an electro-magnetic clutch 94, which forms a disengageable coupling, and which also comprises a further friction plate 96 secured to a spindle 98 mounted in anti-friction bearings and at the lower end of which spindle is formed a squared spigot 100 which is in permanent axial sliding engagement with a squared socket 102 formed in the upper end of an upper portion 104 of a control rod and said spigot 100 is relatively long to permit sufficient longitudinal movement of the socket 102 for performing a fast expansion and contraction of the honing tool 28 as will hereinafter be described.

The electro-magnetic clutch 94 is arranged to be controlled either manually or automatically such as by a timing device or a bore sizing or gauging device so that the two friction plates of said clutch can be disengaged and frictionally engaged with each other as required.

The upper portion 104 of the control rod is provided with a flange 106 on which is mounted, through anti-friction thrust bearings, an annular thrust plate 108 so that the upper portion 104 of the control rod and the annular thrust plate 108 move together longitudinally of the axis XX while, however, said upper portion of the control rod 104 can rotate relatively to the annular thrust plate 108.

Abutting the upper side of the thrust plate 108 are the lower ends of a plurality, for example three, equiangularly spaced apart pistons 110 of fluid-pressure operated piston and cylinder devices also comprising complementary cylinders 1 12 formed in the body 82 and said devices are offset from the longitudinal axis XX and are double-acting and are supplied with hydraulic fluid-pressure through ports 114 and 116. The annular thrust plate 108 is secured to the three pistons by screws 118 so that the upper portion 104 of the control rod is positively moved by the pistons 110 longitudinally of the axis X--X and said piston and cylinder devices 110 and 112 constitute a fast control means such that when the pistons l are urged downwardly by hydraulic pressure the control rod causes a fast expansion of the effective diameter of the honing tool 28 or can permit a fast contraction thereof.

The lower end of the upper portion 104 of the control rod is formed with a blink squared socket 120 with which is engaged so as to abut the end of the socket a squared spigot 122 in the vicinity of a universal joint 124 between the upper and lower portions 46 and 48 of the tubular shaft. The spigot 122 is formed at the upper end of an intermediate portion 126 of the control rod which is spring-urged upwardly by a helical compression spring 128 so that engagement of the spigot 122 with the blind socket 120 is maintained. The lower end of the intermediate portion 126 of the control rod is formed with a blind squared socket 130 which is engaged by a squared spigot 132 at the upper end of a lower portion 134 of the control rod which is urged upwardly by the spring 38 and pushrod 36 so that the spigot abuts the blind end of the squared socket 130.

Disposed in the lower assembly 26 and in the tubular shaft portion 52 thereof is a screw means for effecting a slow and thus powerful feed to increase the effective cutting diameter of the honing tool 28 and this screw means comprises a lead screw 136 formed on the lower control rod portion 134 and a pair of opposite nut members 138 of which both are shown in FIG. 5 but one only is shown in FIG. 4 for convenience and these nut members are rectilineally slidably mounted in the tubular shaft portion 52 so as to be radially movable inwardly into engagement with the lead screw 138 and outwardly out of engagement with said lead screw whilst, however, said nut members 138 are supported so as not to be movable axially,

i.e. longitudinally relatively to the tubular shaft portion 52 and thus of the axis XX.

Each nut member 138 is formed with an inclined plane 140 and a peg 142 which are co-operative respectively with inclined planes 144 and 146 of a nut moving member 148 which is slidably supported by the tubular shaft portion 52 so as to be slidable longitudinally parallel with the axis XX but being prevented from transverse movement.

The upper end of the two nut moving members 148 are each secured by a screw 150 to an annular piston 152 mounted within a cylinder 154 and the upper end of the cylinder is supplied by pneumatic pressure through a passage 156 and a flexible pipe 158 which in turn communicates with passages in the cross-head 66, these passages being indicated 160, 162, 164 and 166 which communicates with a port 168 which can be connected in any suitable manner by a flexible pipe with a source of pneumatic pressure, not shown. Thus, when pneumatic pressure is supplied to the upper end of the cylinder 154 the annular piston 152 is urged downwardly to cause the two nut members 138 to move radially inwardly into engagement with the lead screw member 136 whereas when the pneumatic pressure is discharged or released from the cylinder 154 the annular piston 152 is urged upwardly by six helical compression springs 158 operating between the underside of the annular piston 152- and the location bores in the tubular shaft member 52 whereby the two nut moving members 148 are moved upwardly and operate on the pegs 142 so as positively to move the nut members 138 out of engagement with the lead screw 136. The screw means comprising the lead screw 136 and the nut members 138 comprise a slow feed means to enable slow but powerful and substantially positive expansion of the effective diameter of the honing tool 28 to be caused.

In operation to effect a honing operation in a workpiece tube, the pistons 112 of the fast feed means are considered to be in their upper positions as shown in FIG. 2 and the nut members 138 are out of engagement with the lead screw 136 so that the honing tool 28 is fully contracted by the conventional spring rings or gaiters 170 which draw the stone carriers 42 radially inwardly and the contracted honing tool is moved downwardly into the bore of the workpiece tube by extension of the devices 74. The electric motor 60 is then started to rotate the tubular shaft means 46, 48 and 52 through the fixed ratio gearbox 62 and continued extension and retraction of the devices 74 causes reciprocation of the honing tool 28 longitudinally thereof in the workpiece bore. The fast feed means comprising the piston and cylinder devices and 112 are then operated by introducing hydraulic pressure into the passage 114 whereby the control rod comprising the portions 104, 126 and 134 is urged longitudinally downwardly to urge the push-rod 36 downwardly and cause rapid expansion of the honing tool 28 whereby the honing stones 44 bear on the bore wall of the workpiece tube.

To cause a slow but substantially positive and powerful feed and expansion of the honing tool 28 pneumatic pressure is introduced through the port 168 in the cross-head 66 and into the cylinder 154 to urge the annular piston 152 downwardly whereby the nut moving members 148 are urged downwardly and the nut members 138 are urged radially inwardly by the inclined plane action between the inclined planes 144 and so that the nut members engage the lead screw 136. Providing the electro-magnetic clutch 94 is open, i.e. the friction plates 93 and 96 are not engaged with each other, the lead screw 136 and the control rod portions 126 and 104 are merely rotated with the tubular shaft means at the same speed thereof but when the electro-magnetic clutch is operated so that the two friction plates 93 and 96 thereof are frictionally engaged with each other the rotatable element 88 of the rotational brake means 84 also tends to be rotated but is braked by the drag effect created by the rotational brake means and the hand of the lead screw 136 is such, in relation to the direction of rotation of the tubular shaft means 46, 48 and 52 that the lead screw and thus the control rod portion 134 and the push-rod 36 are forced longitudinally downwardly to cause further and substantially positive expansion of the effective diameter of the honing tool 28. Thus the slow feed or expansion of the honing tool 28 during the honing action is caused as a result of the brake action imposed by the rotational brake means 84 and the braking torque can be adjusted either before or during a honing operation by manually adjusting the control knob 90 of the rotational brake means 84.

The honing operation then proceeds with expansion of the honing tool 28 in either of a number of ways. For example, the nut members 138 may be caused to be disengaged from the lead screw 136 automatically by a sizing device which gauges the size of the bore in the workpiece or instead of the disengagement being effected by the sizing device, the disengagement may be effected by means of a timing or a stroke counting device by which the number of reciprocations of the honing tool are counted. When the nut members 138 are disengaged from the lead screw 136 the honing tool 28 is contracted by the gaiters as a result of the compression springs 38 and 128 urging the control rod vertically upwardly.

Alternatively when the sizing device or the timing or stroke counting devices have operated and the bore of the workpiece tube is substantially finished, the rotational brake means is disengaged but the nut members 138 remain engaged with the lead screw 136 and the honing tool 28 continues to be reciprocated and rotated thus allowing a dwell stroke honing action to be continued for a predetermined time by a stroke counting device to improve the accuracy of the bore in the workpiece tube.

In a still further alternative mode of operation the disengageable coupling 94 is caused to be momentarily engaged and disengaged at predetermined points of the reciprocation cycle of the honing tool whilst the nut members 138 are engaged with the lead screw 136, so that an incremental expansion of the honing tool is obtained as an alternative to the steady continuous expansion obtained when the disengageable coupling 94 remains continuously engaged.

In order to remove the honing tool 28 from the bore of the workpiece tube which is being honed, the pneumatic pressure is exhausted from the upper end of the cylinder 154 to permit the springs 158 to urge the piston 152 upwardly and thus also to urge the nut moving members 148 upwardly whereby the nut members 138 are positively moved radially outwardly and out of engagement with the lead screw 136 by the inclined plane actions developed between the pins 142 and the inclined planes 146 and hydraulic pressure is exhausted from the upper ends of the three cylinders 112 through the ports 114 and is admitted to the lower ends of said cylinders through the ports 116 whereby the annular thrust plate 108 is lifted with the assistance of the springs 128 and 38 which latter also lifts the push-rod 36 to enable the honing tool 28 to be contracted by the gaiters 170. The devices 74 are then contracted.

It should be appreciated that as the slow feed means comprising the lead screw 136 and nut members 138 is disposed at or adjacent that end of the tubular shaft at which the honing tool 28 is positioned, the subjection of the tubular shaft and control rod to compression and tension during forward and return movements respectively of said arrangement whilst reciprocating in the bore of the workpiece tube being honed does not cause variations in the efiective diameter of the honing tool 28 which is of standard design In order to obtain the same beneficial effects of avoidance of variations in the effective diameter of the honing tool a special or non-standard honing tool 28 may be provided as shown in FIG. 6 in which the lead screw 136 is provided on the push-rod 36 of the honing tool and the nut members 138 are slidably mounted in the body 30 or a tubular shaft part 170 permanently secured to the body 30 but otherwise the construction is similar to that illustrated in FIGS. 1 to 5.

It should be appreciated that the honing tool diameter control means herein referred to comprises the control rod composed of the three portions 104, 126 and 134 in FIGS. 1 to 5 and the control rod composed of the three portions 104, 126 and 36 in FIG. 6, the fast feed means comprising the piston and cylinder devices 110 and 112 and the slow feed means comprising the lead screw 136 and the nut members 138.

When a honing tool arrangement as described above has been set up in a honing machine in which a workpiece tube has been loaded, the various operations are performed in proper sequence either automatically or under manual control or a combination of both.

While the nut members 138 are mounted so as to be rectilineally slidable radially with regard to the lead screw 136 and are movable by inclined plane actions, alternatively said nut members may be pivotally mounted about axes parallel with the axis of the lead screw or transverse to said axis but so as, however, during the actual engagement and disengagement of the nut members with or from the lead screw, also to move in a substantially radial manner and said pivoted nut members may be operated other than by inclined plane actions such as for example lever means operated by the annular piston 152.

The invention thus provides a honing tool arrangement of the kind specified which is more efficient than known honing tool arrangements.

1 claim:

1. A honing tool arrangement of the kind comprising a tubular shaft means capable of being rotated about its longitudinal axis and reciprocated axially and of having attached thereto the honing tool to be rotated and reciprocated therewith and also including a honing tool diameter control means including a control rod in the tubular shaft means and capable of being moved longitudinally relatively to the tubular shaft means to increase and decrease the effective cutting diameter of the honing tool said control means also including fast and slow feed means to cause fast and slow changes respectively in the effective cutting diameter of the honing tool and said slow feed means including screw means wherein the improvements provided are a screw member (136) on the control rod (104, 126, 134) and a complementary nut member (138) carried by the tubular shaft means (46, 48, 52) so as to be movable rotationally and longitudinally therewith, said nut member (138) being movable into a disengaged position with the screw means (136) to permit fast feed longitudinal movement of the control rod (104, 126, 134) and being movable into an engaged position with the screw member (136), and rotational brake means (84) associated with the screw means (136, 138) and operative to cause relative rotation of the engaged screw member (136) and nut member (138) while the tubular shaft means (46, 48, 52) is rotating to cause slow feed longitudinal movement of the control rod (104, 126, 134) 2. A honing tool arrangement according to claim 1 wherein the improvement provided is that the brake means (84) is adjustable to vary the braking, that is the "drag" effect, and thus to vary the rate of slow feed longitudinal movement of the control rod (104, 126, 134).

3. A honing tool arrangement according to claim 2 wherein the improvement provided is that the brake means (84) is a liquid brake means relying upon the drag elTect created by a viscous liquid in contact with relatively rotatable brake elements (86, 88).

4. A honing tool arrangement according to claim 3 wherein the improvements provided are that the liquid brake means (84) comprises a non-rotatable element (86) and a rotatable element (88) which latter is connected to the control rod (104, 126, 134) in such a manner as to be rotatable therewith.

5. A honing tool arrangement according to claim 1 wherein the improvements provided are that the nut member (138) of the screw means is mounted so as to be radially movable in the tubular shaft means (46, 48, 52) and has inclined plane engagement (140, 142, 144, 146) with a nut moving member (148).

6. A honing tool arrangement according to claim 5 wherein the improvements provided are that the nut moving member (148) is associated with a fluid-pressure operated piston and cylinder device (152, 154) so as to be moved thereby to cause radial movement of the nut members (138).

7. A honing tool arrangement according to claim 1 wherein the improvement provided is that the screw means (136, 138) is disposed at or adjacent that end of the tubular shaft means (46, 48, 52) at which the honing tool (28) may be positioned to avoid variations occurring in the effective diameter of the honing tool (28) due to the honing tool arrangement being generally alternatively in compression and tension during forward and return movements respectively of said arrangement in the bore of the workpiece tube being honed.

8. A honing tool arrangement according to claim 1 wherein the improvement provided is that the screw means (136, 138) is disposed in the honing tool (28) itselfto avoid variations occurring in the effective diameter of the honing tool (28) due to the honing tool arrangement being generally alternatively in compression and tension during forward and return movements respectively of said arrangement in the bore of the workpiece tube being honed.

9. A honing tool arrangement according to claim 1 wherein the improvement provided is that fast feed control means comprises a fluid-pressure piston and cylinder device 1 10,1 12).

10. A honing tool arrangement according to claim 9 wherein the improvements provided are that the fast feed control means comprises a plurality of fluid-pressure piston and cylinder devices (110,112) disposed offset from the longitudinal axis of the apparatus, said devices being non-rotatable about the longitudinal axis of the apparatus and associated with the control rod (104, 126, 134) so as to permit rotation thereof.

11. A honing tool arrangement according to claim 1 wherein the improvement provided is that the screw means (136) is associated with the rotational brake means (84) through a disengageable coupling (94) so that when said coupling is disengaged the brake means (84) is rendered ineffective and cannot alter the efiective diameter of the honing tool (28) so that said honing tool can perform a dwell stroke" honing action to improve the accuracy of the bore in the workpiece tube being honed.

12. A honing tool arrangement according to claim 1 1 wherein the improvement provided is that the disengageable coupling (94) is a friction clutch coupling.

13. A honing tool arrangement according to claim 12 wherein the improvement provided is that the friction clutch coupling is an electro-magnetically operated coupling (94).

14. A honing machine wherein the improvement provided is that a honing tool arrangement according to claim 1 is incorporated in the machine. 

1. A honing tool arrangement of the kind comprising a tubular shaft means capable of being rotated about its longitudinal axis and reciprocated axially and of having attached thereto the honing tool to be rotated and reciprocated therewith and also including a honing tool diameter control means including a control rod in the tubular shaft means and capable of being moved longitudinally relatively to the tubular shaft means to increase and decrease the effective cutting diameter of the honing tool said control means also including fast and slow feed means to cause fast and slow changes respectively in the effective cutting diameter of the honing tool and said slow feed means including screw means wherein the improvements provided are a screw member (136) on the control rod (104, 126, 134) and a complementary nut member (138) carried by the tubular shaft means (46, 48, 52) so as to be movable rotationally and longitudinally therewith, said nut member (138) being movable into a disengaged position with the screw means (136) to permit fast feed longitudinal movement of the control rod (104, 126, 134) and being movable into an engaged position with the screw member (136), and rotational brake means (84) associated with the screw means (136, 138) and operative to cause relative rotation of the engaged screw member (136) and nut member (138) while the tubular shaft means (46, 48, 52) is rotating to cause slow feed longitudinal movement of the control rod (104, 126, 134).
 2. A honing tool arrangement according to claim 1 wherein the improvement provided is that the brake means (84) is adjustable to vary the braking, that is the ''''drag'''' effect, and thus to vary the rate of slow feed longitudinal movement of the control rod (104, 126, 134).
 3. A honing tool arrangement according to claim 2 wherein the improvement provided is that the brake means (84) is a liquid brake means relying upon the drag effect created bY a viscous liquid in contact with relatively rotatable brake elements (86, 88).
 4. A honing tool arrangement according to claim 3 wherein the improvements provided are that the liquid brake means (84) comprises a non-rotatable element (86) and a rotatable element (88) which latter is connected to the control rod (104, 126, 134) in such a manner as to be rotatable therewith.
 5. A honing tool arrangement according to claim 1 wherein the improvements provided are that the nut member (138) of the screw means is mounted so as to be radially movable in the tubular shaft means (46, 48, 52) and has inclined plane engagement (140, 142, 144, 146) with a nut moving member (148).
 6. A honing tool arrangement according to claim 5 wherein the improvements provided are that the nut moving member (148) is associated with a fluid-pressure operated piston and cylinder device (152, 154) so as to be moved thereby to cause radial movement of the nut members (138).
 7. A honing tool arrangement according to claim 1 wherein the improvement provided is that the screw means (136, 138) is disposed at or adjacent that end of the tubular shaft means (46, 48, 52) at which the honing tool (28) may be positioned to avoid variations occurring in the effective diameter of the honing tool (28) due to the honing tool arrangement being generally alternatively in compression and tension during forward and return movements respectively of said arrangement in the bore of the workpiece tube being honed.
 8. A honing tool arrangement according to claim 1 wherein the improvement provided is that the screw means (136, 138) is disposed in the honing tool (28) itself to avoid variations occurring in the effective diameter of the honing tool (28) due to the honing tool arrangement being generally alternatively in compression and tension during forward and return movements respectively of said arrangement in the bore of the workpiece tube being honed.
 9. A honing tool arrangement according to claim 1 wherein the improvement provided is that fast feed control means comprises a fluid-pressure piston and cylinder device (110,112).
 10. A honing tool arrangement according to claim 9 wherein the improvements provided are that the fast feed control means comprises a plurality of fluid-pressure piston and cylinder devices (110,112) disposed offset from the longitudinal axis of the apparatus, said devices being non-rotatable about the longitudinal axis of the apparatus and associated with the control rod (104, 126, 134) so as to permit rotation thereof.
 11. A honing tool arrangement according to claim 1 wherein the improvement provided is that the screw means (136) is associated with the rotational brake means (84) through a disengageable coupling (94) so that when said coupling is disengaged the brake means (84) is rendered ineffective and cannot alter the effective diameter of the honing tool (28) so that said honing tool can perform a ''''dwell stroke'''' honing action to improve the accuracy of the bore in the workpiece tube being honed.
 12. A honing tool arrangement according to claim 11 wherein the improvement provided is that the disengageable coupling (94) is a friction clutch coupling.
 13. A honing tool arrangement according to claim 12 wherein the improvement provided is that the friction clutch coupling is an electro-magnetically operated coupling (94).
 14. A honing machine wherein the improvement provided is that a honing tool arrangement according to claim 1 is incorporated in the machine. 